One ok Rock.

oor is the initials of One ok Rock. ONE OK ROCK (ワンオクロック) is a Japanese rock band founded in 2005 and officially debuted in 2007. With solid musical skills, cutting-edge music styles and passionate live performance, they have firmly developed into a powerful group with outstanding status and are sought after by fans around the world. The current members of the band include vocalist Taka, guitarist Toru, bassist Ryota, and drummer Tomoya.

The origin of the band name ONE OK ROCK

The band name ONE OK ROCK was inspired by their often scheduled recording studio time One o'clock. Because the band members were still in high school when they first started rehearsing, they could only rehearse on weekends, so they usually started rehearsing from 1 a.m. on Saturday (that is, 1 a.m. on Sunday) until the morning. Because "R" and "L" have the same pronunciation in Japanese, and "O'C" was changed to "OK", their band name came to be.